describe('Validation basics', () => {
  it('validates age successfully', () => {
    const result = validateAge(25)
    expect(result._tag).toBe('Right')
    if (result._tag === 'Right') {
      expect(result.right).toBe(25)
    }
  })

  it('rejects invalid age', () => {
    expect(validateAge(-5)._tag).toBe('Left')
    expect(validateAge(150)._tag).toBe('Left')
  })

  it('validates email successfully', () => {
    const result = validateEmail('user@example.com')
    expect(result._tag).toBe('Right')
  })

  it('rejects invalid email', () => {
    const result = validateEmail('invalid-email')
    expect(result._tag).toBe('Left')
  })
})